Axiom Home Page Forums General Discussion Home Theater 600 Twin

Wow-
Nice post, Doug!

Thanks Mark, much appreciated. As you know, this only touches the surface of the topic. It is fun though!

BTW, if anyone is interested in learning more about the BFD, its capabilities and its complexities, check out:

http://www.snapbug.ws/bfd.htm

if you've not run across it before. It also has some nifty tutorials referenced by the owner of the site, and links to test tones you can download and burn on to a CD. You can also find a link to a handy Excel spreadsheet that can be used in plotting your room FR, with built-in correction factors for the Radio Shack SPL meter (required for the low frequencies we're working with in EQ'ing bass).

Cheers,

Doug

For the Axiom owners in the bay area, Doug has kindly offered his aisstance in setting up the twins and the plan is to do this on Thursday 6/14 starting about 9am. Any one in the area interested in bass set up is welcome as well.

Wish I could be there. I'm sure my room is a nightmare if I were to take all the readings and graph them. I know it sounded much better in my last apartment than it does now.

We have a guest room/bath and its only a 5 hour drive, as long as you get out of the LA area before rush hour.

In reply to:

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I was going to post a "Father of all Bass Posts" showing how I was using a spectrum analyzer, my charts and graphs, etc...but since I didn't finish setting everything up.....

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If it's even half as comprehensive/insightful as your previous "mother of all" posts, we're in for a treat.

I'd be interested in hearing your impressions Mark. I was about to go pick up a BFD the other day and it just so happened the store wasn't opened so I am planning on going this weekend. Unfortunately, my TV is now on the fritz and in the shop so I am waiting to do my measurements with the Rives test cd until everything is back in it's rightful place.

In reply to:

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I'd be interested in hearing your impressions Mark.

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Unfortunately, I won't be able to do anything soon. It's sitting in my rack in "bypass" mode, as I only got the preliminary stuff done.

As I've mentioned a few times here (!), my little square room sux. I really need to find a way to diffuse/absorb some big peaks, and I haven't figured out what to do about the bass nulls yet. After reading so many good things about the BFD, I figured it's worth a try for my bass issues. The plan will be to tame those huge peaks so I can bring the overall level higher…hopefully helping some of the nulls and valleys.

As mentioned previously, I started by creating a test disc of tones followed by some production and commercial music samples for bass listening. When all was said and done, I ended up with three discs of tracks. I also redesigned the bass frequency plot I made to reflect the finer resolution of these samples. So I was finally ready to start charting test tones, but thought that I had better absolutely confirm the sub location before the BFD comes into play. So, after testing and listening, I did end up moving the sub to a new location. The results are only marginally better, but right now I'll take "better" as "better".

So there sits the BFD. My "before" charts are plotted for the three primary listening locations, the BFD is installed, but I have no time to learn and adjust the unit. I'll be gone to a "family thing" in NY for a 3-day weekend and, considering I'm backed up now, I know I'll be even further backed up in my work when I return.

I'm irritated that the fine tuning is taking me so long with the whole HT….. which is entirely due to my lack of free time. It's kind of sad actually that it took me so long to fine tune my speaker positions (I've had my system since last Fall and only tweaked the M60s' positions this past weekend, to good result I'll add). I still have such basic things to do as finish programming my MX700… I think Ray gave up on me!

And yet, I still can't help thinking how much fun it could be to tame this room and write another "parent" post…. Though it really will be nowhere near the length of the last one. Realistically, it just might be a month before that actually happens!

I can't personally vouch for the BFD, but I would still recommend it to others based on so many other positive results others have reported. My biggest concern was that, in my room, the bass changes significantly in just a few feet as I walk around the room. My "before" metering has left me feeling optimistic about the results I might get: Though there are differences across the three main seats, they're not nearly as significant as in other areas of the room. Meaning, in other words, that the three seats are sharing "variations" of the same peaks and therefore I can hope the BFD will improve ALL three seating positions… not one at the loss of another as I first feared.

I'll post… and there will be lots of pix…. But it might not be too soon! Don't wait for me!

Mark brings up a good point that I didn't mention in my previous post and that is doing some experimenting with sub (and speaker) location can tame the room a bit.

As I mentioned to Dennis, EQ is not always necessary and the type of EQ device doesn't always have to be parametric or a BFD. Doing some measurements and playing with sub position in the room is always the best place to start, not to mention if you do decide to EQ at some point, it can give you tremendous insight into the behavior of your room so you can use both position and EQ, as well as treatments, to get things more under control. This assumes though that you know how far out of control things are in the first place.

The neat thing about the equalizers we use for bass, and the thing that makes them a must for tweakers is how cheap they are (relative to our other toys that is...). For $100 you can get a lot of value if you've got a crazy room, or if nothing else have the peace of mind that you've done what you can with what you've got to improve your low end (bass, that is). In my case it was also necessary due to the fact my subs are where they are due to room layout and a small dose of WAF, so I had to go the EQ route just because I can't move the subs. Also since mine are not co-located, it was almost a given I was going to have issues.

For bass heads, or those that just love the punch of a good movie soundtrack, doing a bass FR plot is just the next step after setting speaker levels. And, since we already have the tools to do the measurements (the biggest deal is just having a SPL meter), it's a straightforward exercise.

Maybe when Mark is done and has posted his pics, we'll see his room looks like Axiom's anechoic chamber (extreme room treatment as we like to say), but the FR will be ruler flat... :-)

Enjoy the bass,

Doug

About to call FedEx and see where the driver is, is only about 3 hours late. Well waiting, decided on where to install the BFD, so after an hour with a coping saw, hammer, and chisel, its in place. Posted a couple pictures of it on the web page, opinions are welcome.

Thanks for the info on the BFD, by the way. Very informative post. Is there ever an end to the tweaking?